CHAPTER V 



STEMS 



46. Introductory. — The great object in life for most 

 steins appears to be to get the leaves which they bear in 

 good position with reference to hght. The roots seem to 

 strive to place the root-hairs advantageously as to mois- 

 ture and the stems seem to strive to place the leaves ad- 

 vantageously as to light. Many things other than leaf 

 position affect the character of stems, and many stems 

 have nothing to do with getting leaves into the light, yet, 

 speaking of stems in general, it is fair to call them the 

 leaf-related organs. Principally, they serve the leaves. 



To have leaves high in the air and root-hairs well-placed 

 in the soil seem to be the ends for which many plants 

 are striving. In the forests high leaves and deep roots are 

 secrets of plant success, for leaves high in air are almost 

 sure to get light enough and roots deep in soil are almost 

 sure to get water enough. Shade and drought are enemies. 

 To overcome them is the first great task of the plant. 

 In forests, where hosts of plants compete, the struggle for 

 light and water goes on all the time. The cultivation of 

 plants by man, the whole art of agriculture, has consisted 

 chiefly in making this struggle easier for the plants useful 

 to man. 



It is with the struggle for light that stems are princi- 

 pally concerned. The history of forests is the history of 



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